The entire disclosure of Japanese Patent Application No. 2002-106004 filed on Apr. 9, 2002, including specification, claims, drawings and summary, is incorporated herein by reference in its entirety.
1. Field of the Invention
This invention relates to a vehicle body structure which forms an engine compartment and a passenger compartment by a skeleton.
2. Description of the Related Art
FIG. 5 is a plan view of a vehicle body frame showing a conventional vehicle body structure.
In the conventional vehicle body structure, as shown in FIG. 5, right and left front side members 001 are disposed along a fore-and-aft direction in right and left side portions of a vehicle body. The right and left front side members 001 each have a closed cross-sectional shape, and have front end portions bonded together by a front bumper reinforcement 002. Rear end portions of the respective front side members 001 are curved outward, and are bonded to front end portions of right and left front side sills 003. Rear end portions of the respective front side sills 003 are bonded to a rear seat cross member 004. Right and left front floor side members 005 are disposed inwardly of the front side sills 003, and have front end portions bonded to the rear end portions of the front side members 001, and have rear end portions bonded to the rear seat cross member 004, etc. Furthermore, a dash panel 006 for separating an engine compartment and a passenger compartment is disposed between the right and left front side members 001. A cross member dash 007 of a closed cross-sectional shape is fixed to the dash panel 006, and right and left end portions of the cross member dash 007 are bonded to the front side members 001.
Thus, when a collision load is inputted to the front bumper reinforcement 002 by front collision, this input load is transmitted via the front side members 001 to the front side sills 003 and the front floor side members 005, and to the cross member dash 007, and absorbed thereby, so that the deformation of the passenger compartment can be prevented.
According to the above-described conventional vehicle body structure, the rear end portions of the front side members 001 are bonded to the front side sills 003 and the front floor side members 005, and the cross member dash 007 is disposed along the dash panel 006 disposed between the right and left front side members 001. Because of these features, the input load at the time of collision is distributed to and absorbed by the respective members, and the respective members of a closed cross-sectional shape are adapted to accommodate the load sufficiently. However, the cross member dash 007 has a closed cross-sectional shape, but its right and left end portions are bonded to the front side members 001. Thus, its strength is insufficient to prevent the deformation of the passenger compartment reliably in response to the input load.
At the time of a lapped collision, in particular, a great load is imposed on one side of the vehicle body. Thus, conventional measures taken have been to increase the plate thickness of the front side member 001, and add reinforcement members. These measures have induced increased costs and an increase in the weight of the vehicle body.
Among conventional vehicle body structures, there is the one disclosed, for example, in Japanese Unexamined Utility Model Publication No. 1992-9378. The device disclosed in this publication, entitled xe2x80x9cA vehicle body front structurexe2x80x9d, comprises a cross member formed along a vehicle width direction so as to be curved rearward, front side members having rear portions bonded to the projection of the cross member, and front pillars having end portions of the cross member bonded thereto. In this xe2x80x9cvehicle body front structurexe2x80x9d, however, the cross member is formed in a curved shape, and as in the aforementioned conventional vehicle body structure, deformation is inhibited merely by the rigidity of the cross member itself in response to input load. The xe2x80x9cvehicle body front structurexe2x80x9d, having this feature, is insufficient in strength for preventing the deformation of the passenger compartment.
The present invention has been accomplished in an attempt to solve the problems with the earlier technologies. Its object is to provide a vehicle body structure designed to increase safety by imparting sufficient strength to a skeletal portion of a vehicle compartment, without inducing an increase in cost and an increase in the weight of a vehicle body.
A vehicle body structure according to the present invention, designed to attain the above object, comprises: a dash panel member provided to separate an engine compartment and a passenger compartment of a vehicle, the dash panel member taking a nearly flat shape in a middle portion thereof, and bending and extending to the rear of the vehicle from opposite side portions of the middle portion; a cross member extending in a vehicle width direction along the dash panel member and assuming a closed cross-sectional shape in cooperation with the dash panel member; and side members disposed in side portions of the engine compartment, extending from the front side of the vehicle toward bent portions of the cross member for connection to the bent portions, and extending below a floor panel of the vehicle.
Thus, a load inputted to the side members by collision in the fore-and-aft direction of the vehicle is inputted to the bent portions of the cross member, and is transmitted from the bent portions in such a manner as to be distributed in the longitudinal direction of the cross member. This input load is thus absorbed and supported by the cross member, so that the deformation of the passenger compartment can be prevented reliably.
In the vehicle body structure, the cross member may be fixed to a front surface of the dash panel member, and may be composed of a straight-line portion located in a middle area, the bent portions, and inclined portions extending rearward in a straight line from the bent portions. Thus, the load inputted to the bent portions of the cross member is transmitted from the bent portions in such a manner as to be distributed to the straight-line portion and the bent portions. Consequently, this input load can be absorbed efficiently.
In the vehicle body structure, brace members may be laid between, and connected to, the side members and the bent portions of the cross member. Thus, the use of the brace members obviates the need to manufacture the side member in a complicated shape, so that the machining cost can be reduced. Besides, the brace member is provided in various sizes and shapes, whereby collision characteristics suitable for various vehicle classes can be exhibited.
In the vehicle body structure, the side member may have a rear portion gently curved downward and extending rearward, and the side member and the brace member may together take a nearly straight-line form and the brace member may be connected to the bent portion of the cross member. Thus, the collision load is properly transmitted from the side members to the cross member via the brace members. Consequently, this input load can be absorbed efficiently.
In the vehicle body structure, floor side members may be disposed inwardly of side sills disposed in side portions of the passenger compartment, and the side members may have rear portions gently curved downward and may have rear end portions bonded to the floor side members. Thus, the collision load is transmitted from the side members to the cross member, and is also transmitted to the side sills and the floor side members. Consequently, this input load can be absorbed efficiently.
In the vehicle body structure, opposite side portions of the cross member may extend in the longitudinal direction of front pillars of the vehicle. Thus, the load inputted to the cross member is transmitted in the extending direction of the front pillars, so that this input load can be efficiently absorbed by the front pillars.
In the vehicle body structure, the cross member may have inclined portions extending rearward in a straight line from the bent portions so as to be inclined upwardly, and rear end portions of the inclined portions may be bonded to the front pillars. Thus, the inclined portions of the cross member can be easily located adjoining the front pillars, so that the collision load inputted to the cross member can be efficiently absorbed.